add: new version simplify the rgb alg

setup.py

@@ -20,7 +20,7 @@
     # Versions should comply with PEP440.  For a discussion on single-sourcing
     # the version across setup.py and the project code, see
     # https://packaging.python.org/en/latest/single_source_version.html
-    version='1.1.2',
+    version='1.1.3',
 
     description='A development tool for grabbing the dominant color or representative color palette from an image.',
     long_description='Haishoku is a development tool for grabbing the dominant color or representative color palette from an image, it depends on Python3 and Pillow.',